More bad press for Salt pools...

[quicktime]

Even if you change your chlorine source, you'll still have salt in your water. Sometimes that salt level far exceeds what is needed to operate a SWG.

Boy I can vouch for this. .

Behold my folly:

I just switched from liquid Chlorine to a salt system a couple weeks ago.
I did the math for my pool size and determined the amount to get me 2600 ppm salt, and I figured I had maybe 500 ppm in the water and that I would be low-mid range and trim up to optimum salt levels.
My Circupool RJ60+ started showing high salt ( 5000 ppm) after a couple days and I got some Taylor test strips and they read 5000 as well. I had ordered a Taylor salt test kit but got in a hurry and didn't want to wait before I added the salt.

My test kit arrived and verified that I did indeed have a sudden burst of stupidity by getting in a hurry... 5200 ppm.. haaa haaaa...
Break out the pump and dump about 8000 gallons of water, re-fill, wait a couple days and test again. 3200 ppm. ok , just a little more to get me close to 34-3500 ppm.
Then we get almost 8 1/2 inches of rain in a 24 hour period, after being bone dry all summer in N Texas.
The pool got a pretty good enema courtesy of Mother Nature and I just tested my salt this evening and it knocked out about 200 ppm, back to 3000.

I did bump my CYA from 50 to 70 and that pretty much stayed, so there is one thing going for me.
Going to wait a day or two more and re-test and trim back up.


As far as the "Salt pool will destroy your coping/ rust your pool furniture/ make your dog question it's gender", etc, it's never made sense to me either based on all the reading I have done here and other places.
I believe I have read that the salt in a "salt pool" pretty much doesn't evaporate, so if that statement is true, how does it cause all the damage ?

As stated above, contractors use it as a cop-out for shoddy work.

 

[wireform]

QuickTime
Please explain how you lost only salt and no cya with the fresh rain.

 

[quicktime]

I cant really explain it, I was at 70 prior to the rain and still at 70 this evening.
It was a little later today when I tested than when I checked on Saturday , so the lighting might have made a difference?

I plan on testing again tomorrow as soon as I get home from work with better ambient lighting. I thought and expected I would be down as well.

 

[mgtfp]

If I read that right, then the salt loss was 200 down from 3200. Scaled to 70ppm CYA, that would be a loss of about 4ppm - well with in the test accuracy of the CYA test.

 

[generessler]

Interesting stuff. My last chemistry class was 40+ years ago, so take this with a grain of (wince) salt...

I looked around at a few legitimate-looking sources and the concern with sea water seems to be primarily about magnesium and sulphur compounds that don't seem to apply to a pool.

The ones about road salt effects seem mostly like this one:

"Salt does not damage concrete, but the effects of salt can. That sounds weird, so we’ll explain. Salt does not chemically react with hardened concrete. Salt does however lower the freezing point of water, attract moisture, and increase pressure of frozen water. Salt can also increase the freeze-thaw cycles if the temperature fluctuates between 15°F and 25°F. Concrete scaling can occur in the absence of salts too if there were problems at installation."​

​

Emphasis added. Again I'm not seeing the applicability to pools.

Our pool is 15 years old and afaik has been a salt pool for most of that time. (The SWG was apparently broken for 2 years; it was at ~2000 ppm when we moved in; we've owned for 2.5.) The sandstone coping looks good. Mortar needs repointing, but that's the same 30 yards away from the pool, too. The plaster looks good. No leaks. No visible corrosion anywhere.

 

[sbcpool]

If I read that right, then the salt loss was 200 down from 3200. Scaled to 70ppm CYA, that would be a loss of about 4ppm - well with in the test accuracy of the CYA test.

I learned last night how sensitive the CYA test is to small variations. I had tested my pool a day or two previously at 60 CYA and added 3 lbs CYA. After it dissolved and circulated for a while I tested at ... 60 CYA. Wut? So I got my graduated cylinder out to get some precision and used that to mix precisely equal parts of water and CYA reagent. Then it read 80 CYA.

Even though I had eyeballed the pool water to the bottom of the sticker on the TF-100 and the reagent to the top of the sticker, there was still enough error to make the difference. Then finding the precise point where that dot disappears is another exercise in fun as it depends on the angle of light and how far you hold it from your eye, but that's for another discussion.